Graft anchor devices, systems and methods

ABSTRACT

The present disclosure provides medical devices, systems and methods and in particular to devices and methods useful for anchoring graft materials to bodily structures.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional ApplicationNo. 61/681,988, filed Aug. 10, 2012 and entitled “GRAFT ANCHOR DEVICES,SYSTEMS, AND METHODS,” which application is incorporated herein byreference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to medical devices and inparticular to devices and methods useful for anchoring graft materialsto bodily structures.

BACKGROUND

Implant materials that facilitate tissue ingrowth, such as grafts, maybe used in the medical arts, particularly in applications involvingvascular replacement, augmentation, and/or repair. These materials maybe naturally-derived or non-naturally-derived, and when they areimplanted within a patient, cells and other bodily substances from thepatient can infiltrate the material, leading to, for example, new tissuegrowth on, around, and/or within the implanted material. Tissue ingrowthmay enhance the biocompatibility of such implants, but excessive tissuegrowth may result in unwanted complications.

Such grafts and graft anchoring devices may be used in implantableVentricular Assist Devices (VAD) to create inflow and outflow conduitsthat interface with the circulatory system. Control of cellular ingrowthhas been one of the main challenges for such devices when implanted forlong periods of time.

SUMMARY

The present disclosure provides, in certain aspects, unique methods andsystems for anchoring graft materials to the walls of bodily structures.Some methods and systems involve anchoring a first graft component to awall of a bodily structure, wherein new tissue growth on, around, and/orwithin the first graft is facilitated. The first graft component isintended to provide a cuff structure to allow the anchoring of a secondgraft component easily. The second graft and first graft component mayhave the same or substantially similar material, biologicalcharacteristics, mechanical characteristics, and/or dimensions.Alternatively, the second graft component may have distinct material,biological characteristics, mechanical characteristics, and/ordimensions from the first graft component. The graft could be formed oftwo or more similar or different components.

In another embodiment, the disclosure provides a graft formed bycomponents that have different characteristics that could be joinedtogether to give different characteristics to different parts of thegraft.

In another embodiment, the disclosure provides techniques to limitcellular ingrowth to the proximal component of the graft but not toother components; therefore cellular propagation is limited to one ormore components but not to all components.

In another embodiment, the disclosure provides techniques used to havedifferent diameter grafts joined in such a way that a vortex could beformed in sections of the graft to enhance “washout” effect in certainsections of the graft and therefore limit any cellular growth orattachment in such sections of the graft.

In another embodiment, the disclosure provides techniques used to have asingle graft that is equipped by internal deformity to intentionallycreate a vortex in the flow in order to disrupt any cellular buildup insuch area.

In another embodiment, the disclosure provides techniques used to have asingle graft having different internal structure or characteristics indifferent regions to enhance certain reaction or behavior in certainregions while other sections inhibit certain reactions and behaviors.

In one embodiment a vascular graft is provided. The vascular graftincludes at least one conduit having a first conduit region and a secondconduit region. The vascular graft further includes at least oneperturbation formed in the conduit in the second conduit region, theperturbation configured to cause a vortex in the second conduit region.

The first conduit region may include a first material and the secondconduit region may include a second material distinct from the firstmaterial. The first material may include silicone rubber. The secondmaterial may include porous ePTFE. The second material may include wovenDacron®.

The at least one perturbation may decrease the inner diameter of theconduit region. The at least one perturbation may be tapered.

The first conduit region and the second conduit region may havesubstantially the same diameter.

The vascular graft may include a blood flow assist system coupled to theat least one conduit.

Another embodiment provides a vascular graft that includes at least oneconduit having a first conduit region and a second conduit region. Thesecond conduit region includes a bulbous portion with respect to thefirst conduit region. The graft further includes at least one firstsupport strut positioned in the first conduit region. The at least onefirst support strut is formed in a spiral configuration. The graftfurther includes at least one second support strut position in thesecond conduit region.

The at least one second support strut may be sutured to an outer wall ofthe bulbous portion of the second conduit region.

The at least one second support strut may be composed of stainless steelwires.

The system may include a blood flow assist system coupled to the atleast one conduit.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent) are contemplated as being partof the inventive subject matter disclosed herein. In particular, allcombinations of claimed subject matter appearing at the end of thisdisclosure are contemplated as being part of the inventive subjectmatter disclosed herein. It should also be appreciated that terminologyexplicitly employed herein that also may appear in any disclosureincorporated by reference should be accorded a meaning most consistentwith the particular concepts disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The skilled artisan will understand that the drawings are primarily forillustrative purposes and are not intended to limit the scope of theinventive subject matter described herein. The drawings are notnecessarily to scale; in some instances, various aspects of theinventive subject matter disclosed herein may be shown exaggerated orenlarged in the drawings to facilitate an understanding of differentfeatures. In the drawing, like reference characters generally refer tolike features (e.g., functionally similar and/or structurally similarelements).

FIG. 1 shows a graft made of two components having different diameterand different characteristics in accordance with exemplary inventiveembodiments.

FIG. 2 shows a single graft having an internal structure to form avortex that will limit any cellular buildup in that area in accordancewith exemplary inventive embodiments.

FIG. 3 shows a single graft with two areas including distinct internalstructural characteristics that exhibit different reaction and behaviorin the presence of blood flow in accordance with exemplary inventiveembodiments.

FIG. 4 illustrates a conduit having support structures in accordancewith exemplary inventive embodiments.

FIG. 5 shows a counterpulsation system in accordance with exemplaryinventive embodiments.

FIGS. 6 and 7 illustrate surgical implanting of a graft component inaccordance with exemplary inventive embodiments.

FIGS. 8 and 9 show how the two flanges of graft components are coupledin accordance with exemplary inventive embodiments.

FIGS. 10A and 10B show side cross sectional views of the coupled graftcomponents of FIGS. 8 and 9.

FIG. 11 shows a bubble or enlarged area constructed by “splitting” thebubble in the middle of the hemisphere.

FIG. 12 shows a cross sectional view of a graft component in accordancewith exemplary inventive embodiments.

FIG. 13 shows an arrangement of the “bubble” or enlarged area of graftmaterial located away from the anastomosis.

FIGS. 14A and 14B illustrate a pump connected to a graft component inaccordance with exemplary inventive embodiments.

The features and advantages of the inventive concepts disclosed hereinwill become more apparent from the detailed description set forth belowwhen taken in conjunction with the drawings.

DETAILED DESCRIPTION

Following below are more detailed descriptions of various conceptsrelated to, and exemplary embodiments of, inventive devices, systems,and methods for providing a graft anchor.

While the present disclosure may be embodied in many different forms,for the purpose of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of the disclosure is thereby intended. Any alterations andfurther modifications in the described embodiments and any furtherapplications of the principles of the present disclosure as describedherein are contemplated as would normally occur to one skilled in theart to which the disclosure relates.

The present disclosure provides, in certain aspects, a vascular graft102 that comprises a first component 101 equipped with a suturing cuff105 and a second component 102 equipped with another suturing cuff 103.First component 101 could be attached to a vessel 104 using commonlypracticed suturing techniques or any other mechanical or non-mechanicalanastomotic method. In some embodiments, first component 101 is madefrom a material that enhances cellular ingrowth in order to enhancegraft biocompatibility. As such the material may by example be a porousEPTFE or a woven Dacron material.

The second component 102 may be smaller in diameter and equipped with asuturing cuff 103 to allow easy joining of first component 101 andsecond component 102 by means of commonly used sutures or any othermechanical or non-mechanical anastomotic methods.

The distal tip of the second component 102 typically protrudes insidethe first component 101 and is somewhat concentric forming a gutter typecircular annulus in between component 101 and component 102. Blood cellsmay deposit in this gutter and will as intended define thetransition/boundary/seam between the cell ingrown to the smooth non cellingrown area. In addition, second component 102 is made out of materialthat within the inner lumen inhibits cellular ingrowth or attachment,e.g. by a smooth and thin Silicone layer; therefore cellular ingrowthwill be limited to first component 101. To further promote uninterruptedingrowth defined by a smooth and thin layer of cells growing from thevessel into the first component 101, the first component 101 has beendesigned by its stiffness and potentially bellowed structure to serve asa shock absorbing agent for any blood pumping device, which may beattached to component 102. The shock absorbing agent manages to absorbany flow/pressure induced axial movement and as such helps to facilitateuninterrupted cell ingrowth in the preferred region. As such motioninduced by the pumping device will not disturb the ingrowth, which maylead to continuous cell overgrowth, narrowing of the orifice and toirregular granular tissue, which also could dislodge and create ischemicevents. While ingrowth into first component 101 is wanted, ingrowth ontothe outside surface of first component 101 has to be avoided by cellinhibiting surface agents e.g. Silicone coating, since an overgrowthonto the outside of first component 101 could otherwise lead to targetvessel deformation, which inherently may limit the orifice of the vesselnear the anastomosis.

Due to the difference in lumen diameter between first component 101 andsecond component 102 a vortex is typically formed at vortex area 106located in the proximity of the junction area of first component 101 andsecond component 102. Vortex area 106 serves as an area to limit thecontinual ingrowth or cellular attachment at vortex area 106.

In a different embodiment, the present disclosure provides, in certainaspects, a vascular graft 107 that is formed from a single or multipletubular components that have similar inner diameter. Internal deformity108 could be integral or added at a later stage of the graftmanufacturing to form a “neck down” area in the inner lumen of graft107. Inner deformity 108 serves as a bump to create a vortex in itsproximity to inhibit cellular ingrowths, cellular attachment, and/orcellular deposit. The two sections of graft 107 separated by innerdeformity 108 could be similar or different in biologicalcharacteristics, mechanical characteristics, and/or physical reaction toblood contact. While the area of graft 107 distal to internal deformity108 may be surface treated to inhibit cellular ingrowth, the proximalarea is designed to promote cellular ingrowth from the vessel onto thegraft.

In a different embodiment, the present disclosure provides, in certainaspects, a vascular graft 203 that is formed by one or multiple zones,for example first zone 201 and a second zone 202, that make a singlegraft that possesses different biological characteristics, mechanicalcharacteristics, and/or physical reaction to blood contact. In oneembodiment zone 201 is infiltrated with Silicone rubber to inhibitcellular ingrowth, while zone 202 is of a porous/rough nature promotingingrowth. The mating line between zone 201 and 202 is without a physicalstep, which avoids any unwanted overgrowth of cells from zone 202 ontozone 201.

FIG. 4 illustrates a support stent for a conduit, e.g., for use as agraft with a counterpulsation device (CPD). The conduit includes endports and a passage there between that includes an enlarged area, e.g.,bulb shaped portion. In some embodiments, e.g., when used with a CPD,blood may flow through the conduit in alternating direction. The conduit401 includes a spiral support structure 403 on a first conduit region.Conduit 401 includes a bulbous portion 402 having a plurality of supportstructure 404 coupled thereto. Support structures 403 and 404 may becomposed of stainless steel wire and may be coupled to the conduit viasutures in accordance with exemplary embodiments. The bulbous portion402 may be flexible inwardly and outwardly to permit washing of thetransition region. The bulbous portion 402 may be fabricated using agraft, such as a 20 mm graft, that is cut and sewn into the bulb shapeillustrated in FIG. 4.

The conduit may be supported by a stent structure. In some embodiments,the support structure includes a first portion that includes one or moresupport struts shaped to form the bulb portion. In some embodiments, theouter surface of the material of the bulb portion of the conduit (e.g.,PTFE or other suitable material), may be attached to the struts. In someembodiments, during use, this arrangement allows the bulb portion of theconduit to flex, e.g., to promote washing of the conduit passage

In some embodiments, the support stent may include a second portion thatsupports a non-bulb shaped portion of the conduit (e.g., a portion witha substantially constant cross section). In some embodiments, the secondportion may include a spiral shaped support structure. In someembodiments, the struts of the first portion of the support structuremay be connected to the second portion of the support structure.

The support stent may be made of any suitable material (e.g., abiocompatible material with sufficient structural properties to supportthe conduit), including e.g., stainless steel or a shape memory materialsuch as Nitinol.

In some embodiments, the conduit may be formed by one or multiple zones,for example first zone and a second zone, that make a single graft thatpossesses different biological characteristics, mechanicalcharacteristics, and/or physical reaction to blood contact.

In one embodiment the first zone is infiltrated with Silicone rubber toinhibit cellular ingrowth, while the second zone is of a porous/roughnature promoting ingrowth. The mating line between zones may be withouta physical step, which avoids any unwanted overgrowth of cells from thefirst zone to the second zone. Other embodiments may feature othertransition shapes.

In some embodiments, the first zone may correspond to the bulb shapedportion while the second zone corresponds to the other portion, or viceversa.

One form of a counterpulsation system usable with inventive embodimentsdisclosed herein is shown in FIG. 5. Here a pump 10 is implanted in apacemaker pocket on the patient's right side. Blood fills the pump 10 onone side and air or other fluid fills a sac or bladder (not shown) onthe other side of the pump 10. An air drive line 12 is tunneled from thepacemaker pocket to a skin exit site 14, so the entire pump 10 is underthe skin and can remain there chronically. After the driveline 12 exitsthe skin. It is attached to a small air drive unit 16 that controlsshuttling of pressurized air in and out of the pump 10. A void in thepump 10 may be formed with the sac or bladder. The void fills with airas the heart beats (less cardiac work in ejecting blood) and empties toreturn blood into the circulation (more flow to the patient). The pump10 is attached to the circulation with a conduit 20. The conduit 20shuttles blood between the patient's circulatory system and the pump 10.This situation allows a patient to have chronic counterpulsation withfull mobility. For a patient with severe and potentially non-reversiblecardiac dysfunction, this is a great advantage as it is possible to livea relatively normal life, apart from the need to carry a small batterypowered drive console 16.

As described, the blood is shuttled in and out of the pump 10 with aconduit 20, which is connected, to the circulation. There are a numberof considerations related to implantation and use of this conduit 20.First, almost every conduit has blood flowing in one direction, but thisconduit 20 has blood alternating flow direction two times for each heartbeat as the pump 10 fills and empties with each cardiac cycle. Thiscreates a number of important issues, which will be described. A secondpotential difficulty with a conduit in this situation is that it willtypically be sewn to the subclavian artery 22 or axillary artery whichis located beneath the clavicle and often quite deep, so it istechnically difficult for a surgeon to suture the end of the conduit 20to the artery 22.

The problem of a conduit with bidirectional flow relates to theresponses of blood and tissues to the interfaces with syntheticmaterials and the response is dependent on the direction of flood flow.Many medical devices, such as blood pumps, are connected to thepatient's circulation with artificial graft material such as polyestermaterials like Dacron® or expanded, porous Teflon® (ePTFE) that willpromote tissue or cell ingrowth. The inside of blood pumps is generallysmooth and composed of metals or plastics. When blood flows from asmooth metal or plastic blood pump into a synthetic graft (such aspolyester), the interface where the pump meets the conduit (plastic ormetal to synthetic graft) is a stable junction and there tends to belittle problem when blood flows forward through this junction.

Unfortunately, experience has shown that when blood instead flows from asynthetic graft such as polyester into a smooth surfaced blood pump, adeposit of blood elements including platelets and fibrin tends todeposit at the junction of the two materials—principally on thesynthetic graft and overhanging the Inflow to the pump. These deposits,especially platelets, tend to attract more blood elements and large andoften fragile deposits occur at this junction. These deposits can breaktree from the junction and enter the blood pump and be sent through thepatient's circulation. These deposits can flow anywhere, but if theyarrive in an artery to the brain, a stroke can result. For this reason,many successful blood pumps employ a smooth synthetic conduit (such assilicone or urethane) for blood inflow into the pump.

The problem with counterpulsation is that blood is flowing in analternating bidirectional manner. One solution would be to use a smoothsilicone or urethane conduit, which would create a stable junctionbetween the pump and the conduit where the blood enters into the pump.This solves the problem at the Inflow to the pump. However, when asilicone material is anastomosed (sewn) to an artery, the junctiondevelops a heavy deposit of blood material (fibrin and platelets). Somerely replacing the inflow conduit with a silicone surface is notsatisfactory, it is tempting to merely have a silicone conduit and add afabric extension, but this merely moves the problem that occurs at thejunction of the rough textured surface of the graft and the pump to thejunction between the graft and the silicone tube or cannula.

FIG. 8 shows one exemplary solution in a cross-sectional view. Thesubclavian artery 22 is shown at the top of the figure. A “bubble” orenlarged area 24 of Dacron®. Teflon® or other material is sewn to theartery 22. A silicone or other smooth material conduit portion 26 isconnected to the other side of the enlarged area 24. Rather than adirect junction, a special Interface is created. The smooth siliconesurface portion 26 extends with a tip portion 26 a several millimetersinside the enlarged area 24 of fabric or other material. The walls ofthe silicone tip portion 26 a do not contact the fabric or material ofthe enlarged area or bubble 24, this avoids a silicone-to-fabric (orsmooth-to-rough) point of contact.

Heart valves have been constructed with arrangements to avoid tissueingrowth into the valve by creating an elevation—so that there is not acontinuous connection between the fabric surface and the smooth surface.This elevation prevents tissue from growing over into junction point andcreating a point where platelets and fibrin are deposited. The use of asmall washer of material may also be of use. FIG. 12 shows a smallwasher 28 around the base of the tip 26 a that may help arrest theattachment of blood elements.

FIG. 13 shows that this arrangement of the “bubble” or enlarged area 24a of graft material is located away from the anastomosis. Specifically,enlarged area 24 a is coupled to or includes an extension 24 b that isanastomosed to the artery 22. Other features may be as describedpreviously.

FIGS. 14A and 14B show a similar arrangement can be made at the junctionof the pump 10, Here, the plastic, metal or other smooth surfacedjunction or tip portion 10 a of the pump 10 is separated from the roughsurface of the enlarged graft material by a bubble interface 24 a. Anextension 24 b of the graft material is sewn on the artery 22 (FIG. 13)as previously described. Another extension 24 c on the opposite end mayfacilitate connection to the pump interface or tip portion 10 a, alongwith a suitable connector 28. The junction or Interface 10 a, whichserves as an inlet/outlet port that extends into, but does normally notcontact, the graft material 24 a in use.

These devices with bubbles or enlargements could be made in one piece.As described previously, the subclavian artery 22 is located fairly deepand the incision is small. So a surgeon who is trying to sew a graftwith a bubble or enlargement on it is working in a deep hole. The bubbleor enlargement on the end of a graft obscures his view of the artery. Itwould be useful to avoid this problem and also satisfy the need formaintaining the arrangement where the smooth and rough surfaces are notin direct linear contact.

Such a solution is shown In FIGS. 6 and 7. Here, a graft element formfrom material such as described above is sewn to the artery. The graftelement 30 has a flange 32 at one end. The element 30 is small and easyto move around, so does not obscure the view of the surgeon. FIG. 7shows that it is easy to sew this element 30 around an opening 22 a onthe artery 22.

FIG. 8 shows how a junction between the silicone material portion 26 ofthe conduit 20 and the graft element 30 is recreated when a rim orflange 34 of sewing material or graft material, for example, of theconduit portion 26 is affixed to the flange 32 on the element 30previously anastomosed to the artery 22.

FIG. 9 shows how the two flanges 32, 34 are sewn together. This is avery easy anastomosis to perform.

It will be appreciated that these flanges 32, 34 could be joined notjust by sutures but by staples, clips, glues, clamps etc.

FIG. 10A shows a side cross sectional view of the two flanges 32, 34coming together.

FIG. 10B shows how the bubble or enlarged connector 30 does not have tobe flat—it could be beveled. Also the connector 30 does not have to be agenerally spherical bubble as shown elsewhere herein. The key is onlythat the enlarged area keeps the silicone and graft surfaces (that Is,smooth and rough flow surfaces) from direct contact at their junctionduring use.

The bubble or enlarged area 36 is quite useful as it allows the graft tomove or “swivel” Inside the bubble 36 and still not contact the wall ofthe bubble 36.

FIG. 10B also shows clips or staples 38 attaching the connector 30 tothe artery 22 and attaching the flanges 32, 34 together.

The conduit portion 26 does not have to be entirely silicone. It couldhave any Inner core that presents a compatible surface to the exposedblood. For example, the inside could be metal, have a metal spiralreinforcement, etc. it could also have graft material inside like ePTFEor other polyester.

The smooth surface does not have to be silicone. This is used asrepresentative of a smooth surface. The surface could be a metal orplastic (such as in the pump connection shown in FIGS. 14A and 14B.)

FIG. 11 shows a bubble or enlarged area 40 constructed by “splitting”the bubble In the middle of the hemisphere. It could be equally possiblein form the junction 42 anywhere In this arrangement; the location atthe hemisphere is merely an example

Alternatively, a more complete bubble could be created and the siliconecannula could be slipped into a defect at the end to perform the samefunction.

It should be noted that the terms used are basically smooth (silicone,plastics, metals) and rough or textured surfaces (Dacron, Teflon,ePTFE). It is also possible to have a tightly woven or knitted materialthat is typically called a textile, but could function as a smoothsurface.

Also, It is possible to create a tightly woven polyester that behaveslike a smooth surface. It could be possible to bring a tightly wovensewable graft into direct contact with a silicone surface without anintervening “bubble” or step.

It may also be important to prevent these conduits from collapsing asthey can be located below the skin and could be crushed by a patientlying on them. Reinforcement of the conduits with plastic or wirespirals or rings can be used here. In addition, extra thicknesses ofpolymer or plastic could be added make them stronger.

In various embodiments, any of the devices and techniques describedherein may be used in any suitable combination with the devices andtechniques described in the Appendices.

As utilized herein, the terms “approximately,” “about.” “substantially”and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed without restricting the scope of these features to the precisenumerical ranges provided. Accordingly, these terms should beinterpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described and areconsidered to be within the scope of the disclosure.

It should be noted that the term “exemplary” as used herein to describevarious embodiments is intended to indicate that such embodiments arepossible examples, representations, and/or illustrations of possibleembodiments (and such term is not intended to connote that suchembodiments are necessarily extraordinary or superlative examples).

For the purpose of this disclosure, the term “coupled” means the joiningof two members directly or indirectly to one another. Such joining maybe stationary or moveable in nature. Such joining may be achieved withthe two members or the two members and any additional intermediatemembers being integrally formed as a single unitary body with oneanother or with the two members or the two members and any additionalintermediate members being attached to one another. Such joining may bepermanent in nature or may be removable or releasable in nature.

It should be noted that the orientation of various elements may differaccording to other exemplary embodiments, and that such variations areintended to be encompassed by the present disclosure. It is recognizedthat features of the disclosed embodiments can be incorporated intoother disclosed embodiments.

It is important to note that the constructions and arrangements ofspring systems or the components thereof as shown in the variousexemplary embodiments are illustrative only. Although only a fewembodiments have been described in detail in this disclosure, thoseskilled in the art who review this disclosure will readily appreciatethat many modifications are possible (e.g., variations in sizes,dimensions, structures, shapes and proportions of the various elements,values of parameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter disclosed. For example,elements shown as integrally formed may be constructed of multiple partsor elements, the position of elements may be reversed or otherwisevaried, and the nature or number of discrete elements or positions maybe altered or varied. The order or sequence of any process or methodsteps may be varied or re-sequenced according to alternativeembodiments. Other substitutions, modifications, changes and omissionsmay also be made in the design, operating conditions and arrangement ofthe various exemplary embodiments without departing from the scope ofthe present disclosure.

All literature and similar material cited in this application,including, but not limited to, patents, patent applications, articles,books, treatises, and web pages, regardless of the format of suchliterature and similar materials, are expressly incorporated byreference in their entirety. In the event that one or more of theincorporated literature and similar materials differs from orcontradicts this application, including but not limited to definedterms, term usage, describes techniques, or the like, this applicationcontrols.

While various inventive embodiments have been described and illustratedherein, those of ordinary skill in the art will readily envision avariety of other means and/or structures for performing the functionand/or obtaining the results and/or one or more of the advantagesdescribed herein, and each of such variations and/or modifications isdeemed to be within the scope of the inventive embodiments describedherein. More generally, those skilled in the art will readily appreciatethat all parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the inventive teachingsis/are used. Those skilled in the art will recognize, or be able toascertain using no more than routine experimentation, many equivalentsto the specific inventive embodiments described herein. It is,therefore, to be understood that the foregoing embodiments are presentedby way of example only and that, within the scope of the appended claimsand equivalents thereto, inventive embodiments may be practicedotherwise than as specifically described and claimed. Inventiveembodiments of the present disclosure are directed to each individualfeature, system, article, material, kit, and/or method described herein.In addition, any combination of two or more such features, systems,articles, materials, kits, and/or methods, if such features, systems,articles, materials, kits, and/or methods are not mutually inconsistent,is included within the inventive scope of the present disclosure.

Also, the technology described herein may be embodied as a method, ofwhich at least one example has been provided. The acts performed as partof the method may be ordered in any suitable way. Accordingly,embodiments may be constructed in which acts are performed in an orderdifferent than illustrated, which may include performing some actssimultaneously, even though shown as sequential acts in illustrativeembodiments.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one embodiment, to A only (optionally including elements other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean including but not limitedto. Only the transitional phrases “consisting of” and “consistingessentially of” shall be closed or semi-closed transitional phrases,respectively, as set forth in the United States Patent Office Manual ofPatent Examining Procedures, Section 2111.03.

The claims should not be read as limited to the described order orelements unless stated to that effect. It should be understood thatvarious changes in form and detail may be made by one of ordinary skillin the art without departing from the spirit and scope of the appendedclaims. All embodiments that come within the spirit and scope of thefollowing claims and equivalents thereto are claimed.

1-15. (canceled)
 16. A vascular graft comprising: at least one conduithaving a first conduit region and a second conduit region, the firstconduit region and the second conduit region being collinear and formedin a single tubular component with an inner lumen, wherein the firstconduit region is connected to a first end of the second conduit region,and a second end of the second conduit region contains an opening forconnection to a vessel; and at least one perturbation formed in theinner lumen and separating the first conduit region and the secondconduit region, the perturbation configured to form a neck down area inthe inner lumen to create a vortex in the second conduit region, whereinan area of the graft distal to the at least one perturbation isconfigured to inhibit cellular ingrowth, and an area of the graftproximal to the at least one perturbation is configured to promotecellular ingrowth.
 17. The vascular graft according to claim 16, whereinthe first conduit region includes a first material and the secondconduit region includes a second material distinct from the firstmaterial.
 18. The vascular graft according to claim 17, wherein thefirst material includes silicone rubber.
 19. The vascular graftaccording to claim 17, wherein the second material includes porousePTFE.
 20. The vascular graft according to claim 17, wherein the secondmaterial includes a woven polyester material.
 21. The vascular graftaccording to claim 16, wherein the at least one perturbation decreasesthe diameter of the conduit region.
 22. The vascular graft according toclaim 16, wherein the at least one perturbation is tapered.
 23. Thevascular graft according to claim 16, wherein the first conduit regionand the second conduit region have substantially the same diameter. 24.The vascular graft according to claim 16, further comprising a bloodflow assist system coupled to the at least one conduit.